U.S. patent application number 11/201364 was filed with the patent office on 2007-02-15 for dedicated control channel detection for enhanced dedicated channel.
Invention is credited to Rainer Bachl, Francis Dominique, Hongwei Kong, Walid E. Nabhane.
Application Number | 20070036104 11/201364 |
Document ID | / |
Family ID | 37421146 |
Filed Date | 2007-02-15 |
United States Patent
Application |
20070036104 |
Kind Code |
A1 |
Bachl; Rainer ; et
al. |
February 15, 2007 |
Dedicated control channel detection for enhanced dedicated
channel
Abstract
In a method of detecting a signal, a control channel associated
with a physical channel may be decoded to produce at least one
decoding metric. A control channel signal on the control channel
may then be detected based on the decoding metric.
Inventors: |
Bachl; Rainer; (Nuremberg,
DE) ; Dominique; Francis; (Rockaway, NJ) ;
Kong; Hongwei; (Denville, NJ) ; Nabhane; Walid
E.; (Bedminster, NJ) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 8910
RESTON
VA
20195
US
|
Family ID: |
37421146 |
Appl. No.: |
11/201364 |
Filed: |
August 11, 2005 |
Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04L 1/0054 20130101;
H04B 2201/70709 20130101; H04L 1/0072 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04Q 7/00 20060101
H04Q007/00 |
Claims
1. A method of detecting a signal, comprising: decoding a control
channel associated with a physical channel to produce at least one
decoding metric; and detecting whether a control channel signal is
present on the control channel based on the decoding metric.
2. The method of claim 1, wherein the decoding metric is a
correlation representing the likelihood that a respective codeword
among a plurality of codewords is present in a signal received on
the control channel.
3. The method of claim 2, wherein the decoding metric is a highest
correlation for the plurality of codewords.
4. The method of claim 3, further comprising: calculating an energy
metric based on the highest correlation; and wherein the detecting
step detects whether a control channel signal is present on the
control channel based on the energy metric.
5. The method of claim 4, wherein the calculating step further
comprises: squaring the highest correlation to generate an energy
value; and normalizing the energy value to generate the energy
metric.
6. The method of claim 5, wherein the normalized energy value is
generated based on a signal energy and noise energy for a frame
received on the control channel.
7. The method of claim 4, wherein the detecting step detects that a
control channel signal is present on the control channel based on
the energy metric and a threshold.
8. The method of claim 7, wherein the threshold is dependent on a
number of the codewords in the plurality of codewords associated
with the control channel.
9. The method of claim 7, wherein the threshold is dependent on a
transport format set size associated with a frame received on the
control channel.
10. The method of claim 7, wherein the threshold is determined
based on a maximum number of transmissions for a transport channel
packet.
11. The method of claim 7, wherein the detecting step detects that
a control channel signal is present on the control channel if the
energy metric is greater than or equal to the threshold.
12. The method of claim 1, further comprising: generating an
indicator indicative of whether the control channel signal is
present on the control channel based on the detecting step; and
determining whether to process data received on a data channel
associated with the control channel based on the generated
indicator.
13. The method of claim 1, wherein the physical channel is an
enhanced dedicated channel.
14. An apparatus for detecting a signal, comprising: a decoder for
decoding a control channel associated with a physical channel to
produce at least one decoding metric; and a detector for detecting
whether a control channel signal is present on the control channel
based on the decoding metric.
15. The apparatus of claim 14, wherein the decoding metric is a
correlation representing the likelihood that a respective codeword
among a plurality of codewords is present in a signal received on
the control channel.
16. The apparatus of claim 15, wherein the decoding metric is a
highest correlation for the plurality of codewords.
17. The apparatus of claim 16, wherein the detector calculates an
energy metric based on the highest correlation and detects whether
a control channel signal is present on the control channel based on
the energy metric.
18. The apparatus of claim 17, wherein the detector detects that a
control channel signal is present on the control channel based on
the energy metric and a threshold.
19. The apparatus of claim 18, wherein the detector detects that a
control channel signal is present on the control channel if the
energy metric is greater than or equal to the threshold.
20. The apparatus of claim 18, wherein the threshold is dependent
on a number of the codewords in the plurality of codewords
associated with the control channel.
21. The apparatus of claim 18, wherein the threshold is dependent
on a transport format set size associated with a frame received on
the control channel.
22. The apparatus of claim 18, wherein the threshold is determined
based on a maximum number of transmissions for a transport channel
packet.
Description
BACKGROUND OF THE INVENTION
[0001] A cellular communications network typically includes a
variety of communication nodes coupled by wireless or wired
connections and accessed through different types of communications
channels. Each of the communication nodes includes a protocol stack
that processes the data transmitted and received over the
communications channels. Depending on the type of communications
system, the operation and configuration of the various
communication nodes can differ and are often referred to by
different names. Such communications systems include, for example,
a Code Division Multiple Access 2000 (CDMA2000) system and a
Universal Mobile Telecommunications System (UMTS).
[0002] Third generation wireless communication protocol standards
(e.g., 3GPP-UMTS, 3GPP2-CDMA2000, etc.) may employ a dedicated
traffic channel in the uplink (e.g., a communication flow between a
mobile station (MS) or User Equipment (UE), hereinafter referred to
as a user, and a base station (BS) or NodeB. The dedicated channel
may include a data part (e.g., a dedicated physical data channel
(DPDCH) in accordance with UMTS Release 4/5 protocols, a
fundamental channel or supplemental channel in accordance with
CDMA2000 protocols, etc.) and a control part (e.g., a dedicated
physical control channel (DPCCH) in accordance with UMTS Release
4/5 protocols, a pilot/power control sub-channel in accordance with
CDMA2000 protocols, etc.).
[0003] Newer versions of these standards, for example, Release 6 of
UMTS provide for high data rate uplink channels referred to as
enhanced dedicated channels (E-DCHs). An E-DCH may include an
enhanced data part (e.g., an E-DCH dedicated physical data channel
(E-DPDCH) in accordance with UMTS protocols) and an enhanced
control part (e.g., an E-DCH dedicated physical control channel
(E-DPCCH) in accordance with UMTS protocols).
[0004] FIG. 1 illustrates a conventional wireless communication
system 100 operating in accordance with UMTS protocols. Referring
to FIG. 1, the wireless communication system 100 may include a
number of NodeBs such as NodeBs 120, 122 and 124, each serving the
communication needs of a first type of user 110 and a second type
of user 105 in their respective coverage area. The first type of
user 110 may be a higher data rate user such as a UMTS Release 6
user, referred to hereinafter as an enhanced user. The second type
of user may be a lower data rate user such as a UMTS Release 4/5
user, referred to hereinafter as a legacy user. The NodeBs are
connected to an RNC such as RNCs 130 and 132, and the RNCs are
connected to a MSC/SGSN 140. The RNC handles certain call and data
handling functions, such as, autonomously managing handovers
without involving MSCs and SGSNs. The MSC/SGSN 140 handles routing
calls and/or data to other elements (e.g., RNCs 130/132 and NodeBs
120/122/124) in the network or to an external network. Further
illustrated in FIG. 1 are interfaces Uu, Iub, Iur and Iub between
these elements.
[0005] An example of a frame structure for the enhanced dedicated
channels (e.g., E-DPCCH and E-DPDCH) in the uplink direction is
illustrated in FIG. 2. Each frame 200 may have a length of, for
example, 10 milliseconds (ms) and may be partitioned into 5
sub-frames each including 3 slots. Each slot 205 may have a length
of, for example, 2560 chips, and may have a duration of, for
example, 2/3 ms. Consequently, each sub-frame may have a duration
of 2 ms.
[0006] As discussed above, an E-DCH includes an E-DPDCH 240 and an
E-DPCCH 220, and each of the E-DPCCH 220 and the E-DPDCH 240 may be
code multiplexed.
[0007] The E-DPCCH 220 carries control information for an
associated E-DPDCH 240. This control information includes three
components: a re-transmission sequence number (RSN), a transport
format indicator (TFI) and a happy bit. The RSN indicates the
transmission index of an associated packet transmitted on the
E-DPDCH, has a maximum value of 3 and is represented by two bits.
The TFI indicates the data format for the transport channel carried
by the associated E-DPDCH (e.g., transport block size, transmission
time interval (TTI), etc.) and is represented by 7 bits. The happy
bit is a binary indicator, which may be used by a UE to inform one
or more NodeBs whether the UE is satisfied with the current setup
of the E-DCH channels and is represented by a single bit. For
example, UE 110 of FIG. 1 may use this indicator to inform one of
the NodeBs 120/122/124 that the UE 110 may handle greater data
capacity. In other words, the happy bit is a rate increase request
bit.
[0008] FIG. 3 illustrates a conventional UMTS uplink transmitter
300 located at the enhanced UE 110 of FIG. 1 and a receiver 350
located at one of the NodeBs 120/122/124. The conventional
transmitter 300 and receiver 350 of FIG. 3 may transmit and receive
E-DCHs.
[0009] As shown in FIG. 3, data associated with an upper layer
enhanced dedicated transport channel (E-DCH) may be processed into
E-DPDCH frames at the transmission channel processing block 303.
The frames may be binary phase shift keying (BPSK) modulated and
orthogonally spread at the modulation and orthogonal spreading unit
304. The spread modulated frames are received by the gain unit 315
where an amplitude of the spread modulated frames may be adjusted.
A combiner 320 receives the output of the gain unit 315.
[0010] Still referring to FIG. 3, the 2 RSN bits, the 7 TFI bits
and the 1 happy bit are mapped into a 10-bit E-DPCCH word, which
may be control information for an associated E-DPDCH frame having a
TFI of, for example, 2 ms or 10 ms. The 10-bit E-DPCCH word may
then be coded into a 30-bit coded sequence at an FEC unit 301. That
is, for example, the 10-bit E-DPCCH word associated with a single
E-DPDCH frame is first coded into a 32-bit E-DPCCH codeword using a
(32, 10) sub-code of the second order Reed-Muller code. The 32-bit
codeword is then punctured to (30, 10) code to generate the 30
coded symbols (in this case 1 bit will represent 1 symbol) to be
transmitted. These 30 coded symbols are transmitted in one
sub-frame (e.g., 3 slots with 10-bits per slot).
[0011] Returning to FIG. 3, the 30-bit coded sequence is modulated
at a BPSK Modulator 305 and orthogonally spread at an orthogonal
spreading unit 310. The output from the orthogonal spreading unit
310 is gain adjusted at a gain unit 316 and output to the combiner
320. Similar to the above E-DPCCH, well-known DPCCH frames used in
determining, for example, channel estimates, are modulated at a
BPSK Modulator 306, and the modulated frames are orthogonally
spread at an orthogonal spreading unit 311. The spread modulated
frames are received by a gain unit 317 where an amplitude of the
spread modulated frames may be adjusted.
[0012] The outputs of each of the gain units 315, 316 and 317 are
combined (e.g., code-division multiplexed) into a combined signal
by a combiner unit 320. The combined signal is scrambled and
filtered by a shaping filter 325, and the output of the shaping
filter 325 is sent to the receiver 350 via a propagation channel
330 (e.g., over the air).
[0013] At the receiver 350, the transmitted signal is received over
the propagation channel 330, and input to the E-DPDCH processing
block 335, E-DPCCH soft-symbol generation block 345 and a DPCCH
channel estimation block 355. As is well-known in the art, the
DPCCH channel estimation block 355 generates channel estimates
using pilots transmitted on the DPCCH. The channel estimates may be
generated in any well-known manner, and will not be discussed
further herein for the sake of brevity. The channel estimates
generated in the DPCCH channel estimation block 355 may be output
to each of the E-DPDCH processing block 335 and the E-DPCCH
soft-symbol generation block 345.
[0014] At the soft-symbol generation block 345, the received
control signal may be de-scrambled, de-spread, and
de-rotated/de-multiplexed to generate a sequence of soft-symbols.
The E-DPCCH soft-symbols may represent an estimate of the received
signal, or in other words, an estimate of the 30 symbols
transmitted by the transmitter 300. The E-DPCCH soft-symbols may be
further processed to recover the transmitted E-DPCCH word.
[0015] The E-DPCCH soft-symbols are output to an E-DPCCH
discontinuous transmission (DTX) detection unit 365. The E-DPCCH
DTX detection unit 365 determines whether the signal received on
the E-DPCCH is actually present using a thresholding operation.
[0016] For example, the E-DPCCH DTIX detection unit 365 may
normalize a signal energy for a received E-DPCCH frame (e.g., the
signal energy over a given TTI of 2 ms) and compare the normalized
signal energy to a threshold. If the normalized signal energy is
larger than the threshold, the E-DPCCH DTX detection unit 365
determines that a control signal is present on the E-DPCCH;
otherwise the E-DPCCH DTX detection unit 365 determines that a
control signal is not present on the E-DPCCH and, subsequently,
declares a discontinuous transmission.
[0017] If the E-DPCCH DTX detection unit 365 detects that a control
signal is present on the E-DPCCH, the soft-symbols output from the
soft-symbol generation block 345 are processed by the E-DPCCH
decoding block 375 to recover (e.g., estimate) the 10-bit E-DPCCH
word transmitted by the transmitter 300.
[0018] For example, in recovering the transmitted 10-bit E-DPCCH
word, the E-DPCCH decoding block 375 may determine a correlation
value or correlation distance, hereinafter referred to as a
correlation, between the sequence of soft-symbols and each 30-bit
codeword in a subset (e.g., 2, 4, 8, 16, 32, etc.) of all 1024
possible E-DPCCH codewords, which may have been transmitted by the
transmitter 300. This subset of codewords may be referred to as a
codebook. After determining a correlation between the sequence of
soft-symbols and each of the codewords in the codebook, the E-DPCCH
decoding block 375 selects the 10-bit E-DPCCH word corresponding to
the 30-bit E-DPCCH codeword, which has the highest correlation to
the E-DPCCH soft-symbols. The 10-bit E-DPCCH word is then output to
the E-DPDCH processing block 335 for use in processing the
E-DPDCH.
[0019] The conventional E-DPCCH processing as shown in FIG. 3 is
used to generate E-DPCCH performance results and/or set conformance
test requirements for Release 6 UMTS standards. However, the
performance obtained with this E-DPCCH processing scheme may be
dictated by the E-DPCCH DTX detection unit 365 of FIG. 3, and may
not provide sufficient performance. For example, if an E-DCH has a
TTI length of 2 ms, a higher transmit power may be needed for an
E-DPCCH control signal to be detected at the E-DPCCH DTX detection
unit 365. On the other hand, the E-DPCCH decoding block 375 may
successfully decode E-DPCCH control signals having a lower power
level than that required by the E-DPCCH DIX detection unit 365.
[0020] Accordingly, since the E-DPCCH decoding block 375 only
decodes the E-DPCCH if the E-DPCCH DTX detection unit 365 indicates
that a control signal is present on the E-DPCCH, the E-DPCCH
transmit power must be set based on the performance requirements of
the E-DPCCH detection. This may result in higher power consumption
and/or higher interference to other users.
SUMMARY OF THE INVENTION
[0021] In an example embodiment of the present invention, a method
of detecting a signal may include decoding a control channel
associated with a physical channel to produce at least one decoding
metric and detecting whether a control channel signal is present on
the control channel based on the decoding metric.
[0022] In another example embodiment of the present invention, an
apparatus for detecting a signal may include a decoder and a
detector. The decoder may decode a control channel associated with
a physical channel to produce at least one decoding metric and the
detector may detect whether a control channel signal is present on
the control channel based on the decoding metric.
[0023] In example embodiments of the present invention, the
decoding metric may be a correlation representing the likelihood
that a respective codeword among a plurality of codewords may be
present in a signal received on the control channel.
[0024] In example embodiments of the present invention, the
decoding metric may be a highest correlation for the plurality of
codewords.
[0025] In example embodiments of the present invention, an energy
metric may be calculated based on the highest correlation, and a
control channel signal present on the control channel may be
detected based on the energy metric.
[0026] In example embodiments of the present invention, the highest
correlation may be squared to generate an energy value. The energy
value may be normalized to generate the energy metric. The
normalized energy value may be generated based on a signal energy
and noise energy for a frame received on the control channel.
[0027] In example embodiments of the present invention, a control
channel signal present on the control channel may be detected based
on the energy metric and a threshold. The threshold may be
dependent on a number of the codewords in the plurality of
codewords associated with the control channel, may be dependent on
a transport format set size associated with a frame received on the
control channel and/or may be determined based on a maximum number
of transmissions for a transport channel packet.
[0028] In example embodiments of the present invention, a control
channel signal present on the control channel may be detected if
the energy metric is greater than or equal to the threshold.
[0029] In example embodiments of the present invention, an
indicator indicative of whether the control channel signal is
present on the control channel may be generated based on the
detecting step, and data received on a data channel associated with
the control channel may be processed based on the generated
indicator.
[0030] In example embodiments of the present invention, the decoder
may be an enhanced decoder and the detector may be a discontinuous
transmission detector. The physical channel may be an enhanced
dedicated channel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The present invention will become more fully understood from
the detailed description given herein below and the accompanying
drawings, wherein like elements are represented by like reference
numerals, which are given by way of illustration only and thus are
not limiting of the present invention and wherein:
[0032] FIG. 1 illustrates a conventional wireless communication
system 100 operating in accordance with UMTS protocols;
[0033] FIG. 2 illustrates an example of a conventional frame
structure of enhanced uplink dedicated physical channels;
[0034] FIG. 3 illustrates a conventional UMTS uplink transmitter
and receiver; and
[0035] FIG. 4 illustrates a UMTS uplink receiver according to an
example embodiment of the present invention.
DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS
[0036] As discussed above with regard to FIG. 1, a multi-user
environment may include at least a first type of user 110, which
may be a higher data rate user such as a UMTS Release 6 user,
referred to herein as an enhanced user, and a second type of user
105, which may be a lower data rate user such as a UMTS Release 4/5
user, referred to herein as a legacy user. The enhanced users 10
and the legacy users 105 transmit signals to a serving NodeB
120/122/124 simultaneously over enhanced dedicated channels (e.g.,
E-DPDCHs and E-DPCCH) and dedicated channels (e.g., DPDCHs and
DPCCH), respectively. As discussed above, these enhanced and legacy
dedicated physical channels may be transmitted over respective
propagation channels, each of which may include multiple
propagation paths.
[0037] FIG. 4 illustrates an uplink UMTS receiver 450, according to
an example embodiment of the present invention. The receiver 450
shown in FIG. 4 may be located at, for example, any or all of the
NodeBs 120/122/124 as shown in FIG. 1. For exemplary purposes
example embodiments of the present invention will be discussed with
regard to the conventional wireless system of FIG. 1; however, it
will be understood that example embodiments of the present
invention may be implemented in conjunction with any suitable
wireless telecommunications network (e.g., UMTS, CDMA2000,
etc.).
[0038] As shown in FIG. 4, a transmitted signal is received over
the propagation channel 330, and input to the E-DPDCH processing
block 435, E-DPCCH soft-symbol generation block 345 and a DPCCH
channel estimation block 355. As is well-known in the art, the
DPCCH channel estimation block 355 generates channel estimates
using pilots transmitted on the DPCCH. The channel estimates may be
generated in any well-known manner, and will not be discussed
further herein for the sake of brevity. The channel estimates
generated in the DPCCH channel estimation block 355 may be output
to each of the E-DPDCH processing block 435 and the E-DPCCH
soft-symbol generation block 345.
[0039] At the soft-symbol generation block 345, the received signal
(e.g., received control signal) may be de-scrambled, de-spread, and
de-rotated/de-multiplexed to generate a sequence of soft-symbols.
The E-DPCCH soft-symbols may represent an estimate of the received
signal, or in other words, an estimate of the 30 symbols
transmitted by the transmitter 300. The E-DPCCH soft-symbols may be
further processed to recover the transmitted E-DPCCH word.
[0040] The soft-symbols output from block 345 may be received by
the E-DPCCH decoding unit 475. The E-DPCCH decoding unit 475 may
generate a correlation value or correlation distance (hereinafter
referred to as a correlation) between the soft-symbols (e.g., the
received signal over a given frame or TTI) and each 30-bit codeword
within a known codebook. Each correlation may represent a
likelihood or probability that a respective 30-bit codeword has
been transmitted by the transmitter 300. The known codebook may
include a plurality of 30-bit codewords each corresponding to one
of 1024 possible 10-bit E-DPCCH words. The number of codewords in
the known codebook may be a subset (e.g., 2, 4, 8, 16, 32, etc.) of
all 1024 possible E-DPCCH codewords. The codewords in the codebook
may be determined in any suitable well-known manner and may be
known by the UEs and NodeBs prior to transmission and
reception.
[0041] The E-DPCCH decoding unit 475 may then compare each
correlation to determine the highest correlation. The codeword in
the codebook associated with the highest correlation being the
codeword most likely transmitted by the transmitter 300. This
highest correlation may be used as a decoding metric.
[0042] After determining the highest correlation and associated
codeword in the codebook, the E-DPCCH decoding unit 475 may select
the 10-bit word corresponding to the 30-bit codeword with the
highest correlation metric. The E-DPCCH decoding unit 475 may then
output the decoding metric (e.g., the highest correlation) to the
E-DPCCH DTX detection unit 465 and the selected 10-bit E-DPCCH word
to the E-DPDCH processing block 435.
[0043] In example operation, the E-DPCCH DTX detection unit 465 may
generate an energy metric based on the decoding metric. That is,
for example, the E-DPCCH DTX detection unit 465 may receive the
highest correlation from the E-DPCCH decoding unit 475 and may
square the highest correlation to generate an energy value. The
energy value may represent the signal energy for the E-DPCCH over a
given frame or TTI.
[0044] The E-DPCCH DTX detection unit 465 may also calculate the
energy of the noise over the same E-DPCCH frame or TTI. The signal
energy may be divided by the calculated noise energy to generate a
signal-to-noise ratio or a normalized energy value for the given
E-DPCCH frame or TTI. This normalized energy or signal-to-noise
ratio may be used as the energy metric.
[0045] The E-DPCCH DIX detection unit 465 may then determine if a
control signal has been received in the E-DPCCH frame or TTI based
on the energy metric and a threshold. That is, for example, for a
given E-DPCCH frame or TTI, the E-DPCCH DTX detection unit 465 may
compare the energy metric with the threshold to determine whether a
control signal has been received on the E-DPCCH. If the energy
metric is greater than, or equal to, the threshold, the E-DPCCH DTX
detection unit 465 may determine that a control signal has been
received on the E-DPCCH. On the other hand, if the energy metric is
less than the threshold, the E-DPCCH DTX detection unit 465 may
determine that a control signal has not been received (e.g., no
control signal is present) on the E-DPCCH.
[0046] The E-DPCCH DTX detection unit 465 may then output a binary
DTX indicator indicating whether a control signal has been received
on the E-DPCCH. The binary DTX indicator may have a binary value
`1` or `0`. For example, a binary value `1` may indicate to the
E-DPDCH processing block 435 that a control signal has been
received on the E-DPCCH and a binary value `0` may indicate to the
E-DPDCH processing block 435 that a control signal has not been
received on the E-DPCCH.
[0047] If the E-DPDCH processing block 435 receives a binary DTX
indicator indicating that a control signal has been received on the
E-DPCCH, the E-DPDCH processing block 435 may assume that a data
signal has been received over the same frame or TTI on the
associated E-DPDCH. The E-DPDCH processing block 435 may then begin
to process the associated E-DPDCH. On the other hand, if the binary
DTX indicator indicates that no control signal (e.g., only noise)
has been received over the given frame or TTI on the E-DPCCH, the
E-DPDCH processing block may discard the received signal.
[0048] In example embodiments of the present invention the
threshold may be dependent upon and/or proportional to the number
of codewords in the codebook. That is, the greater number of
codewords in the codebook, the higher the threshold. For example, a
threshold determined based on a codebook having 64 codewords may be
greater than a threshold determined based on a codebook having 4
codewords. As is well-known in the art, the transport format set
size and/or number of transmissions for a transport channel packet
transmitted on the E-DPDCH may be indicative of the codebook size
(i.e., the number of codewords in the subset of codewords to be
used in decoding a received signal). Thus, in example embodiments
of the present invention, the smaller the transport format set size
and/or maximum number of transmissions for a transport channel
packet, the smaller the codebook size and, subsequently, the
smaller the threshold. Accordingly, in example embodiments of the
present invention, the threshold may also, or in the alternative,
be determined based on a transport format set size and/or a maximum
number of transmissions for a transport channel packet.
[0049] In example embodiments of the present invention, the
threshold may be determined based on a false alarm probability. A
false alarm may be when a codeword is detected, but no transmission
by a UE has actually been received by the Node-B. A false alarm
probability may be determined, for example, empirically by a
network operator based on system performance requirements. The
false alarm probability may be specified by a network operator, for
example, at an RNC and may be passed to NodeBs within the network.
In example embodiments of the present invention, a NodeB may
maintain a look-up table, which may be used to convert the false
alarm probability to a corresponding threshold or threshold
value.
[0050] One or more example embodiments of the present invention
provide a more power efficient UE, for example, by reversing the
order of E-DPCCH DTX detection and E-DPCCH decoding. One or more
example embodiments of the present invention provide improved
system performance, for example, for 3GPP Working Group (WG) 4 to
set system performance requirements, reduced interference between
users, increased cell capacity, increased data throughput,
increased battery life and/or increase talk/surf time.
[0051] Example embodiments of the present invention being thus
described, it will be obvious that the same may be varied in many
ways. Such variations are not to be regarded as a departure from
the invention, and all such modifications are intended to be
included within the scope of the invention.
* * * * *